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%I #10 Dec 27 2022 17:52:42
%S 1,2,3,4,5,5,6,7,8,9,9,10,10,11,12,12,13,14,15,15,15,16,17,17,18,18,
%T 18,19,20,21,21,22,23,23,23,23,23,24,25,26,26,27,28,29,30,30,31,31,32,
%U 32,32,33,34,34,34,34,34,35,36,37,37,37,37,38,39,39,40,40,40,41,41,42,42
%N Partial sums of A167020 where A167020(n)=1 iff 6*n-1 is prime.
%C Where A167020 is the characteristic sequence: A167020(n)=1 iff 6*n-1 is prime.
%t Accumulate[Table[If[PrimeQ[6 n-1],1,0],{n,100}]] (* _Harvey P. Dale_, Dec 27 2022 *)
%o (PARI) ism(n) = isprime(6*n-1); \\ A167020
%o a(n) = sum(k=1, n, ism(k)); \\ _Michel Marcus_, Feb 06 2019
%Y Cf. A007528, A167020, A172104.
%K nonn
%O 1,2
%A _Juri-Stepan Gerasimov_, Jan 25 2010
%E Entries checked by _R. J. Mathar_, Apr 14 2010
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